Micro-Scale Technologies for Electronics Cooling

摘要

It has been over fifteen years since this journal had an issue devoted to the subject of electronics cooling. In 1988, volume 9, issue 3 was published, containing nine papers in all: two papers reported on boiling cooling, two on heat pipe applications, three on air-cooling of the board racks, one on heat conduction analysis of the circuit chips, and one on thermal interface management. The 1980s was the era when mainframe computers and other large systems were still regarded as a primary technology driver. Naturally, most of the research topics were defined in the context of applications to large systems. One of the salient attributes common to large systems is the geometric regularity in components' shapes and their placement pattern. In typical settings, one hundred packages of an equal size are mounted in rows and columns on a circuit board, and several circuit boards are stacked with a regular pitch in a cabinet. Another attribute observed in the mainframe computers of the 1980s, typified by a water-cooled single CPU board, is a relatively large space above the high-powered chips. An ample space above the chip means that the coolant can be brought to an individual chip, avoiding complex interactions with heat flows from other chips. Then, heat transfer on the chip becomes a subject of outstanding significance for thermal design. This is a situation where design data can be obtained having a chip or a simulated chip installed in a laboratory apparatus constructed to facilitate instrumentation rather than simulate the structural organization of actual electronic equipment. In analytical work, too, the focus can be set on a zone close to the heat transfer surface where an idealized boundary condition is assumed. These attributes to large systems, the geometric regularity and the criticality of heat transfer on the chip, are reflected in the scope of many papers published in the 1970s and 1980s, including some of those in the 1988 issue of this journal.